The Environmental Mutagenesis Test Development Program (EMTDP) will be generating large volumes of data and experimental information on all chemicals which will be tested for mutagenicity. A computerized data base management system will be required to capture this information in an interactive mode in the testing laboratory, store, process, and analyze the data, and provide summary analyses to the experimenter and to the EMTDP project officers. This system will also allow the EMTDP staff to follow the course of testing with time in the large number of laboratories regardless of the mutagenicity test system being used. The PROPHET system developed and managed under contract to NIH/DRR has been selected. It is being adapted to serve as the EMTDP data base management system.